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krahets
2023-08-20 14:52:42 +08:00
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@ -3795,7 +3795,7 @@ dp[i] = \min(dp[i-1], dp[i-2]) + cost[i]
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<h2 id="1422">14.2.2 &nbsp; 无后效性<a class="headerlink" href="#1422" title="Permanent link">&para;</a></h2>
<p>「无后效性」是动态规划能够有效解决问题的重要特性之一,定义为:<strong>给定一个确定的状态,它的未来发展只与当前状态有关,而与当前状态过去所经历过的所有状态无关</strong></p>
<p>以爬楼梯问题为例,给定状态 <span class="arithmatex">\(i\)</span> ,它会发展出状态 <span class="arithmatex">\(i+1\)</span> 和状态 <span class="arithmatex">\(i+2\)</span> ,分别对应跳 <span class="arithmatex">\(1\)</span> 步和跳 <span class="arithmatex">\(2\)</span> 步。在做出这两种选择时,我们无考虑状态 <span class="arithmatex">\(i\)</span> 之前的状态,它们对状态 <span class="arithmatex">\(i\)</span> 的未来没有影响。</p>
<p>以爬楼梯问题为例,给定状态 <span class="arithmatex">\(i\)</span> ,它会发展出状态 <span class="arithmatex">\(i+1\)</span> 和状态 <span class="arithmatex">\(i+2\)</span> ,分别对应跳 <span class="arithmatex">\(1\)</span> 步和跳 <span class="arithmatex">\(2\)</span> 步。在做出这两种选择时,我们无考虑状态 <span class="arithmatex">\(i\)</span> 之前的状态,它们对状态 <span class="arithmatex">\(i\)</span> 的未来没有影响。</p>
<p>然而,如果我们向爬楼梯问题添加一个约束,情况就不一样了。</p>
<div class="admonition question">
<p class="admonition-title">带约束爬楼梯</p>